A valve timing controller having a vane rotor adjusts a valve opening/closing timing of at least one of an intake valve and an exhaust valve by varying a differential phase between a camshaft and a crankshaft of an engine. JP-2003-120229A and JP-2009-523943A (US-2010-0154732A1) shows a valve timing controller which is provided with a biasing member biasing a vane rotor to the most advanced position or the most retarded position relative to a housing.
In the valve timing controller shown in JP-2003-120229A, a spiral biasing member biases a vane rotor toward the most advanced position relative to a housing. An inner end of the spiral biasing member is engaged with a groove formed in a boss of the vane rotor. An outer end of the spiral biasing member is engaged with bolts which are provided at two positions of the housing. Since a clearance in the spiral biasing member is relatively large, it is likely that the inner end of the spiral biasing member may be disengaged from the groove or displaced from the original position due to centrifugal force applied to the biasing member. If the inner end of the spiral biasing member is displaced radially outwardly, a torque characteristic of the valve timing controller may deviate from the target torque characteristic.
In the valve timing controller shown in JP-2009-523943A, an inner end of the spiral biasing member is formed in hook-shape to be engaged with a pin provided in a vane rotor. However, since an outer diameter of the spiral biasing member is relatively large to be engaged with the pin, a radial size of the biasing member becomes larger, so that a size of the valve timing controller also becomes larger. Moreover, in addition to a pin for engaging the outer end of the biasing member, an additional pin is necessary to engage the inner end of the biasing member, which may increase the number of parts.